A frequency-selective limiter using nuclear magnetic resonance

1 January 1967

journal article
Published by Institute of Electrical and Electronics Engineers (IEEE) in Proceedings of the IEEE

Vol. 55 (1) , 36-45
https://doi.org/10.1109/proc.1967.5375

Abstract

A new device is reported which promises to be of significant value in combating in-band interference. By the application of an inhomogeneous magnetic field to a specially shaped volume of nuclear spins, frequency-selective limiting is obtained over a band of frequencies much larger than the unbroadened NMR (nuclear magnetic resonance) linewidth. The NMR limiter is a passive, self-adaptive-filter with the capability of selectively attenuating signals that are separated in frequency by as little as a few cycles per second. The theory of this device is developed, and experimental results are given for a model operating at 30 MHz with a bandwidth of 1.2 kHz. Suppression by 30 dB of CW interference placed within the sidebands of an AM voice signal has been observed.

Keywords

This publication has 5 references indexed in Scilit:

Multiple-Carrier Behavior of a Frequency-Selective Ferrite Limiter
IEEE Transactions on Communications, 1964
Hyperselective limiter
Proceedings of the IEEE, 1964
Frequency-Selective Limiting
IRE Transactions on Microwave Theory and Techniques, 1962
Dynamic Nuclear Polarization
Reviews of Modern Physics, 1962
Electronic Structure of $F$ Centers: Saturation of the Electron Spin Resonance
Physical Review B, 1953